Ultra small video camera and a video camera system

ABSTRACT

Image data photographed by a video camera 20 is compressed by a compression and decompression circuit 5, the compressed image data is recorded in an incorporated type semiconductor memory 6 or disk-type memory 13 fixed in the video camera 20 and the recorded image data is transferred to an external recording device 23. Further, the external recording device 23 records the transferred image data in a data storage while it is being compressed. The video camera 20 receives, decompresses and converts into a television signal the compressed image data read by the external recording device 23 in a reproducing operation. A video camera system capable of recording and reproducing long hours of image data by using a video camera having an ultra small size comparable to that of an 8 mm video cassette can be realized by using such a construction.

BACKGROUND OF THE INVENTION

The present invention relates to a video camera using a semiconductormemory or a disk-type memory as means for recording images and a videocamera system for use thereof.

In a conventional video camera, as is described in National TechnicalReport, Vol. 37, No. 3, June, 1991, pp.263-272, a video tape recorder(VTR) is used as means for recording images taken by a video camera,wherein the camera and the VTR are accommodated in a single cabinet. Thephotographed images are recorded on a tape through the VTR accommodatedin the cabinet, and long hours of image data can be recorded byperiodically interchanging the VTR tape. However, in such a camera/VTRintegrated camera, it is not possible in principle to provide a VTRportion having a size smaller than that of a cassette of the VTR tape,and, therefore, it has not been possible to realize a video cameracapable of recording and reproducing images and having an ultra smallsize comparable to the size of the cassette.

Accordingly, it has been proposed to realize an ultra small video cameraby compressing image data taken in by a camera and recording the data ina semiconductor memory without using a VTR, as in video camerasdisclosed in Japanese Unexamined Patent Publication No. 253251/1994 andJapanese Unexamined Patent Publication No. 328966/1992. In thetechnology described here, a semiconductor memory is incorporated on anIC card which is attachable to and detachable from a main body of avideo camera, such that a user can freely interchange semiconductormemories in the same manner as a VTR tape.

However, the IC card using a semiconductor memory is generally moreexpensive than a video tape and is not suitable for preserving a largeamount of data generated over a long period of time. On the other hand,when dubbing is to be performed on a video tape by using a separatestationary VTR for preserving a large amount of image data, the timeperiod required for the dubbing is equal to the time period for takingin images, which places an enormous burden on the user. Further, in thiscase, the image data recorded in digital form is converted back to datain analog form, which does not make good use of the digital recording.

Further, in the construction wherein the IC card is attachable anddetachable, the probability of losing data due to static electricity,terminal failure, vibration or the like is enhanced, which significantlylowers its reliability. Meanwhile, in a construction wherein theattaching and detaching of the memory are not possible due to use of asemiconductor memory in the main body of the video camera, only arelatively small amount of image data representing a limited period oftime may be recorded.

SUMMARY OF THE INVENTION

It is an object of the present invention to realize a video cameracapable of recording and reproducing images with its ultra small sizecomparable to that of a video cassette of 8 mm standard and a videocamera system capable of recording image data over a period of manyhours using such video camera.

To achieve the above-mentioned object, the video camera of the presentinvention includes image pickup elements for photoelectricallyconverting optical images to an electrical signal, a driving circuit fordriving the image pickup elements, a signal processing circuit forforming predetermined dynamic image data by performing a predeterminedsignal processing on an output signal of the image pickup elements, acompression circuit for forming compressed image data by performing apredetermined data compression processing on the dynamic image data, afirst memory fixed at an inner portion of the main body of the videocamera for storing the compressed image data and a first digital signaloutputting means for outputting the compressed image data read from thefirst memory to the outside of the main body of the video camera.

Further, a video camera system of the present invention includes theabove-mentioned main body of the video camera and an external recordingdevice which is attachably and detachably connected to the first digitalsignal outputting means of the main body of the video camera and whichhas a first digital signal inputting means to which the compressed imagedata is inputted and a second memory for storing the compressed imagedata inputted by the first digital signal inputting means and having acapacity which is larger than that of the first memory.

The memory incorporated in the main body of the video camera is usedonly for temporarily storing the compressed image data. The compressedimage data is transferred to the external recording device via a cable,light or a public communications network by the digital signaloutputting means after photographing has been finished. Accordingly, thepreservation of a large amount of image data representing a long periodof recording can be performed by the external memory and, therefore, thememory incorporated in the main body of the video camera can be madevery small compared with that in a conventional VTR tape, as in asemiconductor memory or a disk-type memory. Further, if the memory isfixed such that it can not be detached from the main body of the videocamera, the image data will not be destroyed by static electricity orthe like. Further, the transferred data is compressed data and,therefore, the transferring time is very short and the image quality isnot deteriorated since the data is in the form of digital signals.Further, it is possible to transfer the temporarily stored data to theexternal recording device in one's own house etc. by using acommunications network and, therefore, it is not necessary to carry alarge number of tapes when traveling or the like. Further, image datarecorded in a semiconductor memory or on a hard disk in the video cameracan be preserved in an external recording device having a large storagecapacity after photographing has been finished and, therefore, imagedata representing long hours recording can be stored or reproduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more apparent from the following detaileddescription, when taken in conjunction with the accompanying drawings,in which:

FIG. 1 is a block diagram showing an example of a video camera accordingto the present invention;

FIG. 2 is a view showing an example of a semiconductor memory for use ina video camera according to the present invention;

FIG. 3 is a block diagram showing another example of a video cameraaccording to the present invention;

FIG. 4 is a block diagram showing another example of a video cameraaccording to the present invention;

FIG. 5 is a block diagram showing an example of a signal processingcircuit and a compression and decompression circuit for a video cameraaccording to the present invention;

FIG. 6 is a block diagram showing an example of a video camera systemaccording to the present invention;

FIG. 7 is a block diagram showing another example of a video camerasystem according to the present invention;

FIG. 8 is a diagrammatic view showing an example of connections amongelements of a video camera system according to the present invention;

FIG. 9 is a diagrammatic view showing another example of a video camerasystem according to the present invention;

FIG. 10 is a diagrammatic view showing another example of a video camerasystem according to the present invention;

FIG. 11 is a block diagram showing another example of a video camerasystem according to the present invention;

FIG. 12 is a diagrammatic view showing another example of a video camerasystem according to the present invention;

FIG. 13 is a diagram showing another example of a video camera systemaccording to the present invention; and

FIG. 14 is a diagrammatic view showing another example of a video camerasystem according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An explanation will be given of embodiments of the present inventionwith reference to the drawings as follows. FIG. 1 is a block diagramshowing an embodiment of a video camera according to the presentinvention. The video camera 20 is constituted by image pickup elements1, a CDS/AGC circuit 2, an A/D converter 3, a signal processing circuit4, a compression and decompression circuit 5, a semiconductor memory 6,a driving circuit 7, a microcomputer 8, a TV signal input terminal 9, adigital I/O terminal 10, a TV signal output terminal 11, a memorycontroller 12 and a D/A converter 17.

An output terminal of the image pickup elements 1, driven by the drivingcircuit 7, is connected to an input terminal of the CDS/AGC circuit 2.An output terminal of the CDS/AGC circuit 2 is connected to one of twoinput terminals of the A/D converter 3. The TV signal input terminal 9is connected to the other input terminal of the A/D converter 3. Anoutput terminal of the A/D converter 3 is connected to an input terminalof the signal processing circuit 4. An output terminal of the signalprocessing circuit 4 is connected to an input terminal of the D/Aconverter 17. An output terminal of the D/A converter 17 is connected tothe TV signal output terminal 11. Two input/output terminals of thesignal processing circuit 4 are respectively connected to one of fourinput/output terminals of the compression and decompression circuit 5and the microcomputer 8. The other input/output terminals of thecompression and decompression circuit 5 are respectively connected tothe digital I/O terminal 10, the microcomputer 8 and an input/outputterminal of the semiconductor memory 6. The microcomputer 8 is connectedto the driving circuit 7, the signal processing circuit 4, thecompression and decompression circuit 5 and the memory controller 12.The microcomputer 8 controls the semiconductor memory 6 via the memorycontroller 12. Further, the semiconductor memory 6 is attached to theinside of the video camera 20 in a structure wherein a user cannotdetach it therefrom freely which prevents the image data from beingdestroyed by static electricity.

With such a construction, when it is used in the camera mode, an imagesignal is formed by photoelectric conversion by the image pickupelements 1, a processing for reducing noise and a processing for makingconstant the signal level are carried out on the image signal by theCDS/AGC circuit 2 and the image is converted into a digital signal bythe A/D converter 3. Further, when it is used in the line input mode, acomposite image signal inputted via the TV signal input terminal 9 isconverted into a digital signal by the A/D converter 3.

The digital signal outputted from the A/D converter 3 is supplied to thesignal processing circuit 4. In the camera mode, the signal processingcircuit 4 forms a luminance signal and a color-difference signal,modulates the color-difference signal with a color subcarrier and formsa composite image signal by mixing the modulated color signal with theluminance signal. Further, in the line input mode, the signal processingcircuit 4 separates the digital signal into the luminance signal and amodulated color signal and demodulates the modulated color signal into acolor-difference signal.

The composite image signal formed by the signal processing circuit 4 isconverted into an analog signal by the D/A converter 17 and is outputtedfrom the TV signal output terminal 11. Further, both of thecolor-difference signal and the luminance signal, formed by the signalprocessing circuit 4, are supplied to the compression and decompressioncircuit 5 and the data is compressed and recorded in the semiconductormemory 6 and also is outputted from the digital I/O terminal 10. Inreading such image data from the semiconductor memory 6, the compressedcolor-difference signal and luminance signal from the semiconductormemory 6 are outputted to the digital I/O terminal 10 via thecompression and the decompression circuit 5. Further, the compressedimage data is decompressed by the compression and decompression circuit5 and supplied to the signal processing circuit 4. The signal processingcircuit 4 forms a composite image signal by modulating thecolor-difference signal with a color subcarrier and by mixing it withthe luminance signal. The composite image signal is converted into ananalog signal by the D/A converter 17 and is outputted from the TVsignal output terminal 11.

As stated above, in the case of this video camera, no VTR is used;rather a semiconductor memory is used as a recording means and,therefore, the total device can be very much downsized. Further, theimage signal provided by the photographing is compressed and temporarilystored in the semiconductor memory and the recorded image data isoutputted from the digital I/O terminal 10. Therefore, the image signalcan be preserved by transferring it to an external recording devicewhich is provided outside of the video camera 20. The image data isoutputted from the digital I/O terminal as digital data and, therefore,no deterioration of image quality is caused even after dubbing. Further,an input terminal and output terminal for analog TV signal are provided,and therefore, the image signal recorded by an analog VTR or the likecan be preserved in the external recording device by converting it intoa digital signal and the digital data recorded in the semiconductormemory can be seen on a TV monitor. Further, in this video camera thesemiconductor memory is fixed within the structure in such a way thatthe user cannot detach it therefrom freely and, therefore, thesemiconductor memory can be prevented from being damaged or the datatherein destroyed.

FIG. 2 is a view showing a specific example of the semiconductor memory6 in FIG. 1. The semiconductor memory 6 is constituted by laminating aplurality of memory wafers 61 through 65. According to this structure,the memory capacity can be enhanced without increasing the size of theICs of the semiconductor memory 6 and therefore, the amount of the datatemporarily stored in the semiconductor memory 6 can be increasedwithout increasing the size of the video camera 20.

FIG. 3 is a block diagram showing another example of a video cameraaccording to the present invention. Portions corresponding to those inFIG. 1 have been given the same reference numerals and a repeat of theexplanation thereof will be omitted. The difference from the videocamera in FIG. 1 lies in that a hard disk 13 is used in place of thesemiconductor memory 6. Also, this hard disk 13 is attached to the videocamera 20 in such a way that the user cannot detach it freely from theoutside, which prevents destruction of the hard disk due to vibrationaccompanied by attaching and detaching it. A similar effect can beprovided but this video camera as in the video camera of FIG. 1.Further, the memory capacity of the hard disk is generally larger thanthat of the semiconductor memory 6 and therefore, the amount of theimage data temporarily recorded in the video camera can be increased.

FIG. 4 is a block diagram showing another example of a video cameraaccording to the present invention. Further, portions corresponding tothose in FIG. 1 have been given the same reference numerals and a repeatof the explanation thereof will be omitted. The difference from thevideo camera of FIG. 1 lies in that a communication modem 15 and acommunication I/O terminal 16 are additionally provided. Oneinput/output terminal of the compression and decompression circuit 5 isconnected to an input/output terminal of the communication modem 15 andthe other input/output terminal of the communication modem 15 isattached to the communication I/O terminal 16. Thus, the communicationI/O terminal 16 may be connected to a public communications network orthe like. Meanwhile, a user may connect an external recording device,such as a VTR installed in his own house or the like, to thecommunications network. The image data compressed by the compression anddecompression circuit 5, or the compressed image data supplied from thecompression and decompression circuit 5 after being read from thesemiconductor memory 6, is transferred to the external recording devicethrough the communication modem 15 and the communication I/O terminal 16via the public communications network. An effect similar to thatobtained in the video camera in FIG. 1 can also be provided by thisvideo camera and a user can take images for many hours without carryingan external recording device. Further, although the communication modemis incorporated in the video camera 20, it may be provided outside ofthe video camera 20. A similar effect can be obtained by installing thecommunication modem and the communication I/O terminal in the videocamera in FIG. 3.

FIG. 5 shows a specific example of the signal processing circuit 4 andthe data compression and decompression circuit 5 in each of the videocameras of FIG. 1, FIG. 3 and FIG. 4. The signal processing circuit 4has a camera signal processing circuit 34 and a TV signal processingcircuit 35, a modulator 38 and switches 33, 36 and 37. The compressionand decompression circuit 5 has a compression circuit 41, adecompression circuit 42 and switches 39, 43, 44, 45 and 46. Datasupplied to the compression and decompression circuit 5 via the digitalI/O terminal 10 is supplied to the decompression circuit 42 via theswitches 45 and 44. The output data from the decompression circuit 42becomes the output data of the compression and decompression circuit 5via the switch 39. The output data of the compression and decompressioncircuit 5 is inputted to the signal processing circuit 4. The inputteddata is supplied to the modulator 38 via the switches 36 and 37. Theoutput signal from the modulator 38 becomes the output signal of thesignal processing circuit 4. The output signal from the signalprocessing circuit 4 is supplied to the D/A converter 17. Themicrocomputer 8 is connected to the switches 33, 36, 37, 39, 43, 44, 45and 46, the camera signal processing circuit 34, the TV signalprocessing circuit 35, the modulator 38, the compression circuit 41 andthe decompression circuit 42.

An explanation will be given of the operation as follows. The compressedimage data inputted from the digital I/O terminal 10 is decompressed bythe decompression circuit 42 in the compression and decompressioncircuit 5 and is outputted from the compression and decompressioncircuit 5. The image data outputted from the compression anddecompression circuit 5 is inputted to the signal processing circuit 4,modulated by the modulator 38 and outputted from the signal processingcircuit 4. The modulated image signal outputted from the signalprocessing circuit 4 is converted into an analog signal by the D/Aconverter 17. Further, the switches 33, 36, 37, 39, 43, 44, 45 and 46are switched by the microcomputer to perform the above-mentionedoperation. Although the semiconductor memory 6 is used in thisembodiment as a memory incorporated in the video camera 20 for recordingthe image data, it may be replaced by the hard disk 13.

FIG. 6 is a block diagram showing an example of a video camera systemusing the video camera of FIG. 1. Further, although the video camera ofFIG. 1 is used here, either one of the video cameras of FIG. 3 and FIG.4 may be used. An external recording device 23 is connected to the videocamera 20 via the digital I/O terminal 10 and a digital I/O terminal 71.The digital I/O terminal 71 supplies data to a memory controller 14 anda semiconductor memory 18. The semiconductor memory 18 supplies data tothe digital I/O terminal 71 and an attachable and detachable datastorage 32. The memory controller 14 supplies control data to thesemiconductor memory 18. The data storage 32 supplies data to thesemiconductor memory 18.

An explanation will be given of the operation of transferring compressedimage data recorded in the semiconductor memory 6 to the externalrecording device 23 in the video camera system of FIG. 6. The compressedimage data recorded in the semiconductor memory 6 is transferred to thesemiconductor memory 18 via the compression and decompression circuit 5,the digital I/O terminal 10 of the video camera 20 and the digital I/Oterminal 71 of the external recording device 23. Since the compresseddata is transferred through the compression and decompression circuit 5,the data is transferred while it is being compressed. The image datatransferred first to the semiconductor memory 18 is further transferredto the attachable and detachable data storage 32.

Next, an explanation will be given of the operation of converting thecompressed image data recorded in the external recording device 23 intoTV signals by decompressing the data in the video camera system of FIG.6. The compressed image data recorded in the attachable and detachabledata storage 32 is supplied via the semiconductor memory 18, the digitalI/O terminal 71 of the external recording device 23 and the digital I/Oterminal 10 of the video camera 20 to the compression and decompressioncircuit 5 where it is decompossed. The decompressed data are convertedinto TV signals by the signal processing circuit 4, is further convertedinto analog TV signals by the D/A converter 17 and is outputted via theTV signal output terminal 11. The TV signals are displayed as images bybeing inputted to a TV monitor or the like.

According to this video camera system, the semiconductor memory 6, usedas a recording means in the video camera 20, has a capacity necessaryfor temporarily recording a significant amount of data and, therefore,an ultra small video camera can be realized. Further, the compressedimage data can be transferred to the external recording device 23 afterphotographing. The compressed image data recorded in the externalrecording device 23 also can be inputted to the video camera 20,decompressed therein and outputted therefrom as TV signals when thecontent of the external recording device 23 is reproduced, with theresult that many hours of image data can be recorded and reproduced.Further, the image data transferred between the video camera 20 and theexternal recording device 23 is compressed image data and, therefore, itcan be transferred at a high speed. The recording means of the externalrecording device 23 is the attachable and detachable data storage 32and, therefore, the amount of recordable image data is not restricted byinterchanging the data storage 32. When the image data in the videocamera 20 is transferred to the external recording device 23, the datais retransferred to the data storage 32 after being transferred firstinto the semiconductor memory 18 at a high speed and, therefore, thevideo camera 20 is able to complete the transferring operation earlierthan when the data is directly transferred to the data storage 32.Further, it is possible to record and reproduce TV signals inputted fromthe outside, to and from the external recording device 23.

FIG. 7 is a block diagram showing another example of a video camerasystem using the video camera of FIG. 1. In FIG. 7, the semiconductormemory 18 and the data storage 32 in the external recording device 23 inthe system of FIG. 6 are replaced by a hard disk 19. This is used in acase where image data is recorded in a hard disk of a personal computer.An effect essentially similar to that in the system of FIG. 6 can beprovided by this system.

FIG. 8 is a view showing an example of connections among variousapparatuses in a video camera system of the present invention. Here, theexternal recording device 23, a TV monitor 22 and an analog VTR 21 areconnected to the video camera 20. The TV signal input terminal 9 of thevideo camera 20 is connected to the analog VTR 21, the digital I/Oterminal 10 of the video camera 20 is connected to the externalrecording device 23 and the TV signal output terminal 11 is connected tothe TV monitor 22. The video camera 20 and the external recording device23 used here may be any of the above-mentioned ones. However, thecommunication I/O terminal 16 in case of the video camera shown in FIG.4 is not used here. It is possible to transfer the image data recordedin the memory (the semiconductor memory 6 or the hard disk 13)incorporated in the video camera 20 for temporarily recording it in theexternal recording device 23 or to monitor this date using the TVmonitor 22 by connecting the respective apparatuses in such a way. It isalso possible to dub the image data in the external recording device 23through the process as mentioned above after reproducing the data usingthe analog VTR 21 and then inputting the data to the TV signal inputterminal 9 of the video camera 20.

FIG. 9 is a view showing another example of connections among variousapparatuses in a video camera system of the present invention. The videocamera 20 is connected to the TV monitor 22 and a digital VTR 27. Thevideo camera 20 may be any one of those shown in FIG. 1, FIG. 3 and FIG.4. The digital I/O terminal 10 of the video camera 20 is connected tothe digital VTR 27 and the TV signal output terminal 11 of the videocamera 20 is connected to the TV monitor 22. It is possible to transferthe image data recorded in the memory (the semiconductor memory 6 or thehard disk 13) in the video camera 20 for temporarily recording it in thedigital VTR 27 or to monitor the data using the TV monitor 22 byconnecting the respective apparatuses in such a manner.

FIG. 10 is a view showing another example of connections among variousapparatuses in a video camera system of the present invention. The videocamera 20 is connected to a public communications network 24 and acommunication modem 25 is connected to the communications network 24. Apersonal computer 26 is connected to the communication modem 25. Here,the video camera shown in FIG. 4 is used as the video camera 20. Thecommunication I/O terminal 16 of the video camera 20 is connected to thecommunication modem 25 via the public communications network 24. Imagedata is sent to the personal computer 26 via the communication modem 25.In this way, the image data recorded in the memory (the semiconductormemory 6 or the hard disk 13) in the video camera 20 temporarily can beread and transferred from the communication I/O terminal 16 to thecommunication modem 25 via the public communications network 24 byconnecting the respective apparatuses in such a manner. Accordingly, theimage data can be stored in an internal memory of the personal computer26 which is installed at locations different from that of the videocamera 20.

FIG. 11 is a block diagram showing another example of a video camerasystem according to the present invention. This system is alsoconstituted by the video camera 20 and the external recording device 23.The video camera 20 includes the image pickup elements 1, the CDS/AGCcircuit 2, the A/D converter 3, the signal processing circuit 4, thecompression and decompression circuit 5, the semiconductor memory 6, thedriving circuit 7, the microcomputer 8, the memory controller 12, theD/A converter 17, photoelectric converters 28a, 28b and 28c, lightemitting elements 76b and 77b and light receiving elements 76a and 77a.The external recording device 23 includes the semiconductor memory 18,the memory controller 14, photoelectric converters 28d, 28e and 28f,light emitting elements 74b and 75b, light receiving elements 74a and75a, the digital I/O terminal 71, a TV signal input terminal 72 and a TVsignal output terminal 73. The output signal of the image pickupelements 1 driven by the driving circuit 7 is supplied to the CDS/AGCcircuit 2. An optical signal inputted from the light receiving element77a is supplied to the photoelectric converter 28c. The output signal ofthe CDS/AGC circuit 2 and the output signal of the photoelectricconverter 28c are supplied to the A/D converter 3. The output signal ofthe A/D converter 3 is supplied to the signal processing circuit 4. Theoutput signals of the signal processing circuit are supplied to the D/Aconverter 17, the microcomputer 8 and the compression and decompressioncircuit 5. The output signal of the D/A converter 17 is supplied to thephotoelectric converter 28b. The output signal of the photoelectricconverter 28b is supplied to the light emitting element 77b. Thecompression and decompression circuit 5 supplies data to the signalprocessing circuit 4, the semiconductor memory 6, the photoelectricconverter 28a and the microcomputer 8. The photoelectric converter 28asupplies data to the compression and decompression circuit 5 and thelight emitting element 76b. The light receiving element 76a suppliesdata to the photoelectric converter 28a. The microcomputer 8 suppliescontrol data to the driving circuit 7, the signal processing circuit 4,the compression and decompression circuit 5 and the memory controller12. The memory controller 12 supplies control data to the semiconductormemory 6. The light receiving element 76a of the video camera 20 isconnected to the light emitting element 74b of the external recordingdevice 23 through a light path. The light emitting element 76b of thevideo camera 20 is connected to the light receiving element 74a of theexternal recording device 23 through a light path. The light emittingelement 77b of the video camera 20 is connected to the light receivingelement 75a of the external recording device 23 through a light path.The light receiving element 77a of the video camera 20 is connected tothe light emitting element 75b of the external recording device 23through a light path. The light receiving element 74a and light emittingelement 74b are connected to the photoelectric converter 28d. Thephotoelectric converter 28d supplies data to the memory controller 14and the semiconductor memory 18. The semiconductor memory 18 suppliesdata to the photoelectric converter 28d and the digital I/O terminal 71.The memory controller 14 supplies control data to the semiconductormemory 18. The signal received from the light receiving element 75a issupplied to the photoelectric converter 28e. The output signal of thephotoelectric converter 28e is supplied to the TV signal output terminal73. The signal inputted from the TV signal input terminal 72 is suppliedto the photoelectric converter 28f. The output signal of thephotoelectric converter 28f is supplied to the light emitting element75b.

FIG. 12 shows an example of connections among respective componentelements of the video camera system of FIG. 11. The light emittingelement 77b of the video camera 20 is connected to the light receivingelement 75a of the external recording device 23. The light receivingelement 77a is connected to the light emitting element 75b of theexternal recording device 23. The light emitting element 76b of thevideo camera 20 is connected to the light receiving element 74a of theexternal recording device 23. The light receiving element 76a of thevideo camera 20 is connected to the light emitting element 74b of theexternal recording device 23. The digital I/O terminal 71 of theexternal recording device 23 is connected to the digital VTR 27. The TVsignal output terminal 73 and the TV signal input terminal 72 of theexternal recording device 23 are connected to the analog VTR 21. The TVsignal output terminal 73 of the external recording device 23 is alsoconnected to the TV monitor 22. Further, the light emitting elements 76band 77b and light receiving elements 76a and 77a of the video camera 20are optically connected to the light receiving elements 74a and 75a andlight emitting elements 74b and 75b of the external recording device 23,respectively, in a state wherein the video camera 20 is mounted at apredetermined location of the external recording device 23.

Next, an explanation will be given of the operation of the video camerashown in FIG. 11 and FIG. 12. The operation up to the step of recordingthe image data taken in by the video camera in the semiconductor memory6 is similar to that of the example of the video camera of FIG. 1.

First, an explanation will be given of the operation up to the step ofrecording the TV signal inputted from the outside in the semiconductormemory 6 via the external recording device 23. The output signal of theanalog VTR 21 is inputted from the TV signal input terminal 72 of theexternal recording device 23. The TV signal is photoelectricallyconverted in the external recording device 23 and inputted to the videocamera 20 via the light emitting element 75b and the light receivingelement 77a. The TV signal is photoelectrically converted in the videocamera 20 and is further converted into a digital signal by the A/Dconverter 3. The image signal converted into the digital signal issubjected to receives TV signal processings, such as Y/C separation,modulation and the like, by the signal processing circuit 4. The imagedata formed by the TV signal processing is compressed by the compressionand decompression circuit 5 and is recorded in the semiconductor memory6.

Next, an explanation will be given of the operation up to the step oftransferring the compressed image data recorded in the semiconductormemory 6 to the digital VTR 27 via the external recording device 23. Thecompressed image data recorded in the semiconductor memory 6 is inputtedto the photoelectric converter 28a via the compression and decompressioncircuit 5 and is photoelectrically converted. Thephotoelectrically-converted compressed image data is inputted to theexternal recording device 23 via the light emitting element 76b and thelight receiving element 74a. In this case, since the data is transferredvia the compression and decompression circuit 5, the data is transferredwhile being compressed. The image data is photoelectrically-converted bythe photoelectric converter 28d and is transferred to the semiconductormemory 18 by the external recording device 23. The image data is firsttransferred to the semiconductor memory 18 and is then transferred tothe digital VTR 27 via the I/O terminal 71.

Next, an explanation will be given of the operation up to the step ofdisplaying the compressed image data recorded in the digital VTR 27 onthe TV monitor 22 by decompressing the data and converting it into TVsignals. The compressed image data recorded in the digital VTR 27 isphotoelectrically-converted after having been transferred to the digitalI/O terminal 71 and the semiconductor memory 18 of the externalrecording device 23. The photoelectrically-converted image data isinputted to the video camera 20 via the light emitting element 74b andthe light receiving element 76a. The image data inputted to the videocamera 20 is again photoelectrically converted, decompressed by thecompression and decompression circuit 5, converted into TV signals bythe signal processing circuit 4, converted into analog signals by theD/A converter 17 and then photoelectrically-converted. Thephotoelectrically-converted signal is inputted to the external recordingdevice 23, inputted to the TV monitor 22 via the light emitting element77b, the light receiving element 75a and the TV signal output terminal73 by the external recording device 23, and is displayed as images.

This video camera also provides an effect similar to that in FIG. 6.Further, the external recording device 23 becomes a station of a videocamera 20. That is, the video camera 20 and the external recordingdevice 23 are connected by the light emitting elements 76b and 74b andthe light receiving elements 74a and 76a and paths of the TV signals areconnected by the light receiving elements 75a and 77a and the lightemitting elements 77b and 75b. The inputting and the outputting of theTV signals are performed by the TV signal input terminal 72 and the TVsignal output terminal 73 of the external recording device 23.Therefore, when the analog VTR 21 is connected to the TV signal inputterminal 72 and the TV signal output terminal 73, the TV monitor 22 isconnected to the TV signal output terminal 73 and the digital VTR 27 isconnected to the digital I/O terminal 71, in a case where the transferof data is performed among the VTRs 21 and 27 or the TV monitor 22 andthe video camera 20, the transfer can be performed merely by disposingthe video camera 20 on the external recording device 23 which dispenseswith the need for troublesome connecting cables. Further, in a casewhere the total of the video camera 20 is contained in a water-proofpackage for using it in water or the like and the terminals cannot bedisposed at the outside, the transfer of the data can be performed bylight connection. Further, although the transfer of data is performed bythe light connection between the video camera 20 and the externalrecording device 23 in this example, it is more inexpensive to connectthem by metallic terminals without using photoelectric converters, lightreceiving elements and light emitting elements.

FIG. 13 is a block diagram showing another example of a video camerasystem according to the present invention. A battery 81 for the videocamera 20 is connected to an AC adapter 82 incorporated in the externalrecording device 23 via an input terminal 83 for charging, an outputterminal 84 for charging and a comon cable 85. Digital image data istransferred and power is supplied from the AC adaptor to the battery viathe common cable 85. The cable 85 transfers digital image data betweenthe video camera 20 and the external recording device 23 via the digitalI/O terminals 10 and 71 and a DC power generated by an AC power sourceat the AC adapter 82 is supplied to the battery 81 via the outputterminal 84 for charging, the cable 85 and the input terminal 83 forcharging. While the image data is transferred between the video camera20 and the external recording device 23, the battery 81 can be chargedby the AC adapter 82 via the cable 85. Therefore, even when theremaining amount of power in the battery 81 in the video camera 20 isdecreased during the data transferring operation, the battery can simplybe charged simultaneously with the data transferring operation.

FIG. 14 is a view showing another example of a video camera systemaccording to the present invention. As in the system of FIG. 13, thebattery 81 in the video camera 20 is connected to the AC adapter 82incorporated in the external recording device 23 by an input terminal 78for charging and an output terminal 79 for charging. The image data istransferred between the video camera 20a and the external recordingdevice 23 through a light connection. Further, the DC power generated bythe AC power source at the AC adapter 82 is supplied to the battery 81via the output terminal 79 for charging and the input terminal 78 forcharging. The output terminal 79 for charging and the input terminal 78for charging may be of a contact type using metallic terminals or of anon-contact type utilizing electromagnetic induction or the like. Also,in this system as in the system of FIG. 12, the external recordingdevice 23 is a station of the video camera 20 and, therefore, when datais transferred among the VTRs 21 and 27 and the TV monitor 22 and thevideo camera 20, the video camera 20 need only be mounted on apredetermined location of the external recording device 23. Accordingly,there is no need for troublesome connecting cables in transferring data,and the video camera 20 can be charged simultaneously with thetransferring of data as in the system of FIG. 12. Further, as in thesystem of FIG. 12, although data is transferred between the video camera20 and the external recording device 23 by light connection, theconnection may be performed by metallic terminals without usingphotoelectric-converters, light receiving elements and light emittingelements.

We claim:
 1. A video camera comprising:image pickup elements forphotoelectrically converting an optical image; a driving circuit fordriving the image pickup elements; a signal processing circuit forforming predetermined dynamic image data by performing a predeterminedsignal processing on an output signal of the image pickup elements; acompression circuit for forming compressed image data by performing apredetermined data compression processing on the dynamic image data; amemory for storing the compressed image data; a digital signaloutputting means for outputting the compressed image data read from thememory to the outside of a main body of the video camera; a televisionsignal inputting means for inputting television signals from the outsideand a television signal processing circuit for converting the televisionsignals inputted from the television signal inputting means into dynamicimage data; and wherein the compression circuit performs a datacompression processing on the dynamic image data converted by thetelevision signal processing circuit to thereby form compressed imagedata.
 2. A video camera comprising:image pickup elements forphotoelectrically converting an optical image; a driving circuit fordriving the image pickup elements; a signal processing circuit forforming predetermined dynamic image data by performing a predeterminedsignal processing on an output signal of the image pickup elements; acompression circuit for forming compressed image data by performing apredetermined data compression processing on the dynamic image data; amemory for storing the compressed image data; a digital signaloutputting means for outputting the compressed image data read from thememory to the outside of a main body of the video camera; and acommunication circuit for sending the compressed image data read fromthe memory to an outside communications network.
 3. A video camerasystem comprising:(a) a main body of a video camera including:(1) imagepickup elements for photoelectrically converting an optical image; (2) adriving circuit for driving the image pickup elements; (3) a signalprocessing circuit for forming predetermined dynamic image data byperforming a predetermined signal processing on an output signal of theimage pickup elements; (4) a compression circuit for forming compressedimage data by performing a predetermined data compression processing onthe dynamic image data; (5) a first memory for storing the compressedimage data; and (6) a first digital signal outputting means foroutputting the compressed image data read from the first memory to theoutside of the main body of the video camera; and (b) an externalrecording device including:(1) a first digital signal inputting meansattachably and detachably connected to the first digital signaloutputting means of the main body of the video camera for inputting thecompressed image data; and (2) a second memory for storing thecompressed image data inputted by the first digital signal inputtingmeans, said second memory having a capacity larger than a capacity ofthe first memory; wherein the first digital signal outputting means is afirst light emitting element for converting an electric signalrepresenting the compressed image data into a light signal andoutputting the light signal to the outside of the main body of the videocamera, and the first digital signal inputting means is a first lightreceiving element for converting the light signal received from thefirst light emitting element into an electric signal.
 4. A video camerasystem according to claim 3, wherein the external recording devicefurther includes a second digital signal outputting means for outputtingthe compressed image data read from the second memory, and the main bodyof the video camera further includes a second digital signal inputtingmeans attachably and detachably connected to the second digital signaloutputting means of the external recording device for inputting thecompressed image data, a decompression circuit for decompressing thecompressed image data inputted by the second digital signal inputtingmeans, a television signal processing circuit for converting dynamicimage data decompressed by the decompression circuit into a televisionsignal and a television signal outputting means for outputting thetelevision signal to the outside of the main body of the video camera.5. A video camera system according to claim 4, wherein the first digitalsignal outputting means and the second digital signal inputting meansconstitute a first digital signal inputting and outputting terminal fortransferring data in both input and output directions, and the firstdigital signal inputting means and the second digital signal outputtingmeans constitute a second digital signal inputting and outputtingterminal attachably and detachably connected to the first digital signalinputting and outputting terminal.
 6. A video camera system according toclaim 4, wherein the second digital signal outputting means is a secondlight emitting element for converting an electric signal representingcompressed image data into a light signal and outputting the lightsignal to the outside of the external recording device, and the seconddigital signal inputting means is a second light receiving element forconverting the light signal from the second light emitting element againinto an electric signal.
 7. A video camera system according to claim 6,wherein the television signal outputting means is a third light emittingelement for converting the television signal into a light signal andoutputting the light signal to the outside of the main body of the videocamera, and the external recording device further includes a third lightreceiving element for converting the light signal from the third lightemitting element again into an electric signal and a television signaloutput terminal for outputting the television signal from the thirdlight receiving element to the outside of the external recording device.8. A video camera system comprising:(a) a main body of a video cameraincluding:(1) image pickup elements for photoelectrically converting anoptical image; (2) a driving circuit for driving the image pickupelements; (3) a signal processing circuit for forming predetermineddynamic image data by performing a predetermined signal processing on anoutput signal of the image pickup elements; (4) a compression circuitfor forming compressed image data by performing a predetermined datacompression processing on the dynamic image data; (5) a first memory forstoring the compressed image data; and (6) a first digital signaloutputting means for outputting the compressed image data read from thefirst memory to the outside of the main body of the video camera; and(b) an external recording device including:(1) a first digital signalinputting means attachably and detachably connected to the first digitalsignal outputting means of the main body of the video camera forinputting the compressed image data; and (2) a second memory for storingthe compressed image data inputted by the first digital signal inputtingmeans, said second memory having a capacity larger than a capacity ofthe first memory; wherein the main body of the video camera furtherincludes a television signal inputting means for inputting televisionsignals from the outside of the main body of the video camera and atelevision signal processing circuit for forming dynamic image data byperforming a predetermined signal processing on the television signals.9. A video camera system comprising:(a) a main body of a video cameraincluding:(1) image pickup elements for photoelectrically converting anoptical image; (2) a driving circuit for driving the image pickupelements; (3) a signal processing circuit for forming predetermineddynamic image data by performing a predetermined signal processing on anoutput signal of the image pickup elements; (4) a compression circuitfor forming compressed image data by performing a predetermined datacompression processing on the dynamic image data;(5) a first memory forstoring the compressed image data; and (6) a first digital signaloutputting means for outputting the compressed image data read from thefirst memory to the outside of the main body of the video camera; and(b) an external recording device including:(1) a first digital signalinputting means attachably and detachably connected to the first digitalsignal outputting means of the main body of the video camera forinputting the compressed image data; and (2) a second memory for storingthe compressed image data inputted by the first digital signal inputtingmeans, said second memory having a capacity larger than a capacity ofthe first memory; wherein the first digital signal outputting means isconnected to the first digital signal inputting means by mounting themain body of the video camera at a predetermined location with respectto the external recording device and using light communication means toeffect communication therebetween.
 10. A video camera systemcomprising:(a) a main body of a video camera including:(1) image pickupelements for photoelectrically converting an optical image; (2) adriving circuit for driving the image pickup elements; (3) a signalprocessing circuit for forming predetermined dynamic image data byperforming a predetermined signal processing on an output signal of theimage pickup elements; (4) a compression circuit for forming compressedimage data by performing a predetermined data Compression processing onthe dynamic image data; (5) a first memory for storing the compressedimage data; and (6) a first digital signal outputting means foroutputting the compressed image data read from the first memory to theOutside of the main body of the video camera; and (b) an externalrecording device including:(1) a first digital signal inputting meansattachably and detachably connected to the first digital signaloutputting means of the main body of the video camera for inputting thecompressed image data; and (2) a second memory for storing thecompressed image data inputted by the first digital signal inputtingmeans, said second memory having a capacity larger than a capacity ofthe first memory; wherein the external recording device further includesan AC adapter for forming a direct current power source from analternating current power source and a power source output terminal foroutputting direct current from the direct current power source, and themain body of the video camera further includes a power source inputterminal for inputting the direct current from the power source outputterminal and a battery capable of being charged by being supplied withthe direct current inputted via the power source input terminal; andwherein the battery is charged while the compressed image data is beingtransferred from the first digital signal outputting means to the firstdigital signal inputting means.
 11. A video camera system according toclaim 10, wherein the first digital signal outputting means is connectedto the first digital signal inputting means and the power source outputterminal is connected to the power source input terminal by mounting themain body of the video camera at a predetermined location with respectto the external recording device.
 12. A video camera systemcomprising:(a) a main body of a video camera including:(1) image pickupelements for photoelectrically converting an optical image; (2) adriving circuit for driving the image pickup elements; (3) a signalprocessing circuit for forming predetermined dynamic image data byperforming a predetermined signal processing on an output signal of theimage pickup elements; (4) a compression circuit for forming compressedimage data by performing a predetermined data compression processing onthe dynamic image data; (5) a first memory for storing the compressedimage data; (6) a first digital signal inputting and outputting meansfor outputting the compressed image data read from the first memory toan outside of the main body of the video camera and for inputting thecompressed image data from the outside thereof; (7) a decompressioncircuit for forming dynamic image data by performing a decompressionprocessing on the compressed image data inputted by the first digitalsignal inputting and outputting means; (8) a television signalprocessing circuit for forming a television signal by performing apredetermined signal processing on the dynamic image data received fromthe decompression circuit; and (9) a television signal outputting meansfor outputting the television signal to the outside of the main body ofthe video camera; and (b) an external recording device including:(1) asecond digital signal inputting and outputting means attachably anddetachably connected to the first digital signal inputting andoutputting means of the main body of the video camera for inputting thecompressed image data from the main body of the video camera and foroutputting the compressed image data to the main body of the videocamera; and (2) a second memory for storing the compressed image datainputted by the first digital signal inputting and outputting means andfor supplying the stored compressed image data to the second digitalsignal inputting and outputting means, said second memory having acapacity larger than a capacity of the first memory; wherein the firstand the second digital signal inputting and outputting means eachcomprises light emitting elements for convening an electric signalrepresenting the compressed image data into a light signal and foroutputting the light signal to the outside thereof and light receivingelements for converting an inputted light signal into an electricsignal.
 13. A video camera system comprising:(a) a main body of a videocamera including:(1) image pickup elements for photoelectricallyconverting an optical image; (2) a driving circuit for driving the imagepickup elements; (3) a signal processing circuit for formingpredetermined dynamic image data by performing a predetermined signalprocessing on an output signal of the image pickup elements; (4) acompression circuit for forming compressed image data by performing apredetermined data compression processing on the dynamic image data; (5)a first memory for storing the compressed image data; (6) a firstdigital signal inputting and outputting means for outputting thecompressed image data read from the first memory to an outside of themain body of the video camera and for inputting the compressed imagedata from the outside thereof; (7) a decompression circuit for formingdynamic image data by performing a decompression processing on thecompressed image data inputted by the first digital signal inputting andoutputting means; (8) a television signal processing circuit for forminga television signal by performing a predetermined signal processing onthe dynamic image data received from the decompression circuit; and (9)a television signal outputting means for outputting the televisionsignal to the outside of the main body of the video camera; and (b) anexternal recording device including:(1) a second digital signalinputting and outputting means attachably and detachably connected tothe first digital signal inputting and outputting means of the main bodyof the video camera for inputting the compressed image data from themain body of the video camera and for outputting the compressed imagedata to the main body of the video camera; and (2) a second memory forstoring the compressed image data inputted by the first digital signalinputting and outputting means and for supplying the stored compressedimage data to the second digital signal inputting and outputting means,said second memory having a capacity larger than a capacity of the firstmemory; wherein the main body of the video camera further includestelevision signal inputting means for inputting a television signal fromthe outside, and the television signal processing circuit forms thedynamic image data by performing a predetermined signal processing onthe television signal.
 14. A video camera system comprising:(a) a mainbody of a video camera including:(1) image pickup elements forphotoelectrically converting an optical image; (2) a driving circuit fordriving the image pickup elements;(3) a signal processing circuit forforming predetermined dynamic image data by performing a predeterminedsignal processing on an output signal of the image pickup elements; (4)a compression circuit for forming compressed image data by performing apredetermined data compression processing on the dynamic image data; (5)a first memory for storing the compressed image data; (6) a firstdigital signal inputting and outputting means for outputting thecompressed image data read from the first memory to an outside of themain body of the video camera and for inputting the compressed imagedata from the outside thereof; (7) a decompression circuit for formingdynamic image data by performing a decompression processing on thecompressed image data inputted by the first digital signal inputting andoutputting means; (8) a television signal processing circuit for forminga television signal by performing a predetermined signal processing onthe dynamic image data received from the decompression circuit; and (9)a television signal outputting means for outputting the televisionsignal to the outside of the main body of the video camera; and (b) anexternal recording device including:(1) a second digital signalinputting and outputting means attachably and detachably connected tothe first digital signal inputting and outputting means of the main bodyof the video camera for inputting the compressed image data from themain body of the video camera and for outputting the compressed imagedata to the main body of the video camera; and (2) a second memory forstoring the compressed image data inputted by the first digital signalinputting and outputting means and for supplying the stored compressedimage data to the second digital signal inputting and outputting means,said second memory having a capacity larger than a capacity of the firstmemory; wherein the external recording device further includes an ACadapter for forming a direct current power source from an alternatingcurrent power source and a power source output terminal for outputtingdirect current from the direct current power source, the main body ofthe video camera further includes a power source input terminal forinputting the direct current from the power source output terminal and abattery capable of being charged by being supplied with the directcurrent inputted via the power source input terminal, and the battery ischarged while the compressed image data is being transferred from thefirst digital signal inputting and outputting means to the seconddigital signal inputting and outputting means.
 15. A video camera systemcomprising:(a) a main body of a video camera including:(1) image pickupelements for photoelectrically converting an optical image; (2) adriving circuit for driving the image pickup elements; (3) a signalprocessing circuit for forming predetermined dynamic image data byperforming a predetermined signal processing on an output signal of theimage pickup elements; (4) a compression circuit for forming compressedimage data by performing a predetermined data compression processing onthe dynamic image data; (5) a first memory for storing the compressedimage data; (6) a first digital signal inputting and outputting meansfor outputting the compressed image data read from the first memory toan outside of the main body of the video camera and for inputting thecompressed image data from the outside thereof; (7) a decompressioncircuit for forming dynamic image data by performing a decompressionprocessing on the compressed image data inputted by the first digitalsignal inputting and outputting means; (8) a television signalprocessing circuit for forming a television signal by performing apredetermined signal processing on the dynamic image data received fromthe decompression circuit; and (9) a television signal outputting meansfor outputting the television signal to the outside of the main body ofthe video camera; and (b) an external recording device including:(1) asecond digital signal inputting and outputting means attachably anddetachably connected to the first digital signal inputting andoutputting means of the main body of the video camera for inputting thecompressed image data from the main body of the video camera and foroutputting the compressed image data to the main body of the videocamera; and (2) a second memory for storing the compressed image datainputted by the first digital signal inputting and outputting means andfor supplying the stored compressed image data to the second digitalsignal inputting and outputting means, said second memory having acapacity larger than a capacity of the first memory; wherein theexternal recording device further includes an AC adapter for forming adirect current power source from an alternating current power source anda power source output terminal for outputting direct current from thedirect current power sources the main body of the video camera furtherincludes a power source input terminal for inputting the direct currentfrom the power source output terminal and a battery capable of beingcharged by being supplied with the direct current inputted via the powersource input terminal, and the battery is charged while the compressedimage data is being transferred from the first digital signal inputtingand outputting means to the second digital signal inputting andoutputting means; wherein the first digital signal inputting andoutputting means is connected to the second digital signal inputting andoutputting means and the power source output terminal is connected tothe power source input terminal by mounting the main body of the videocamera at a predetermined location with respect to the externalrecording device.